Gun bore wire takeup cone



Sept. 2, 1969 w. P. MORROW 3,464,265

GUN BORE WIRE TAKEUP CONE Filed Oct. 24, 1967 INVENTOR 4 2 WARREN P. MORROW W 1 BY WM W d 6, J, I ATTORNEYS United States Patent 3,464,266 GUN BORE WIRE TAKEUP CONE Warren P. Morrow, Silver Spring, Md., assignor to the United States of America as represented by the Secretary of the Army Filed Oct. 24, 1967, Ser. No. 677,790 Int. Cl. G01] 5/14 U.S. Cl. 73167 5 Claims ABSTRACT OF THE DISCLOSURE The takeup cone comprises a body mounted on the forward end of a projectile and having a conical recess opening through the forward end thereof. A spherical cavity is formed laterally adjacent the apex of the conical opening and an aperture through the conical wall of the body adjacent the apex of the conical opening opens into the spherical cavity. An antenna wire connected to an environmental sensing unit carried by the projectile extends outwardly from the spherical cavity through the aperture into the conical recess and coaxially along a gun barrel for connection with information readout instruments. When the projectile is fired, the wire passes through the aperture and collects in the spherical recess.

BACKGROUND OF THE INVENTION The present invention relates to apparatus for collecting inbore projectile environment data and in particular to a wire takeup cone for projectiles wherein data is collected by the bore wire method.

Conventional methods for collecting ballistic data during movement of a projectile within a gun bore often employ a wire extending from the nose of the projectile outwardly along the bore of a gun for connection with readout instruments whereby various data, such as projectile acceleration, velocity, spin rate, vibration, etc., can be measured. A typical system utilizes a resistance wire fixed to a conductive cone carried in the nose of a projectile, the wire forming a portion of an electrical circuit through the projectile and gun barrel. The wire is connected to suitable measuring instruments whereby progressive collapse of the wire against the nose of the projectile when fired shorts out the portion of the wire so collapsed, thereby changing the effective length and effective resistance of the wire. The resistance change can be recorded to provide velocity and acceleration data. In this system, however, only one channel of information can be monitored. Another typical system which may monitor multievents, employs an antenna wire connected to electrical sensing units carried by the projectile, the antenna wire extending through the nose of the projectile along the barrel of the gun for connection to suitable measuring instruments. In both cases, takeup cones are normally employed to collect the wire as the projectile advances along the gun barrel.

A number of problems arise, however, as the wire is forced into the takeup cone as the projectile advances along the gun barrel, chief among which is the tendency of the wire to break as it impacts within the cone against its point of attachment of the wire to the projectile and against the wire already taken up or collected in the cone. Breaking the wire or losing electrical contact with the conductive cone as in the case of a resistance wire provides erroneous and unreliable data. Additionally, in the case of an antenna wire, ionized gas in the gun bore and necessary modifications required to restrict the gas has caused serious design and test complications. The destructive impact force of the wire against conventional wire takeup cones causes sufficient variation in the collected data as to render the data unreliable.

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Summary of the present invention The wire takeup cone of the present invention comprises a nose body for a projectile having a conical recess opening coaxially through the forward end thereof. A spherical cavity is formed in the body and disposed laterally adjacent the apex of the conical recess. An aperture opens through the wall of the conical recess into the spherical cavity. The apex of the conical recess intersects the periphery of a diametrical plane which extends across the spherical cavity normal to the longitudinal axis of the conical recess. A lead wire extending through an opening in the rear base of the body extends through the spherical recess, through the aperture into the conical recess, and outwardly through the nose of the projectile for connection to suitable measuring instruments. The inner end of the lead wire may connect to a conductor for ultimate electrical connection through the projectile and gun bore to complete a circuit to the measuring instruments where the resistance wire data collection method is employed or may connect to suitable projectile environment sensing units having a self-power source, the sensing units and power source being carried within the projectile.

Upon firing the projectile, the lead wire is taken up and collected in the spherical cavity with the conical recess acting as a guide feeding the wire through the aperture into the spherical cavity. In this manner, the impact of the collecting wire is dissipated over the curved surface of the spherical cavity and wire impact against a flat surface, particularly in the area of the wire-to-cone attachment, which tends to break the wire, is avoided.

Accordingly, it is a primary object of the present invention to provide an improved wire takeup cone for projectiles employed in collecting internal ballistic data.

It is another object of the present invention to provide an improved wire takeup cone for projectiles which virtually eliminates the tendency of the wire to break as the latter is collected in the nose of the projectile.

It is still another object of the present invention to provide an improved wire takeup cone for projectiles wherein impact of the collecting wire against fiat surfaces, against the point of attachment of the wire to the cone, and against previously collected wire is virtually eliminated.

It is a further object of the present invention to provide an improved wire takeup cone for projectiles wherein the cone may be employed with either smooth bore guns or rifled barrel guns.

These and other objects and advantages of the invention will become more apparent upon reference to the following specification, claims, and appended drawings.

Brief description of the drawing figures FIGURE 1 is a fragmentary longitudinal sectional view of a gun bore illustrating the nose of a projectile connected via a lead wire to a measuring instrument;

FIGURE 2 is an enlarged fragmentary longitudinal sectional view taken generally about on line 2-2 of FIGURE 3; and

FIGURE 3 is a staggered cross sectional view thereof taken about on line 33 of FIGURE 2.

Description of a preferred embodiment Referring now to FIGURE 1, there is illustrated a gun barrel 10 and a projectile 12 loaded within barrel 10, projectile 12 having a body portion including a cylindrical outer casing 14 and a nose portion generally indicated at 16. Barrel 10 may have a smooth or rifled bore, as desired. A lead wire 18 extends coaxially along barrel 10 from nose portion 16 and outwardly through the muzzle of barrel 10 for connection to suitable measuring instruments indicated at 20, wire 18 being wrapped about a support 21 (shown coincident with wire 18) to maintain the same coaxial with barrel 10. Lead wire 18 may be of the resist ance wire type and electrically coupled through the projectile and barrel to suitable measuring instruments whereby the change of resistance of the wire as the wire progressively collapses against a conductive nose portion of the projectile is proportional to the displacement of the bullet in barrel 1b with the potential variation of the wire being measured by such instruments and correlated to provide velocity and acceleration measurements. However, in the preferred form hereof, wire 18 is of the antenna type and as seen in FIGURE 2, connected through nose portion 16 to suitable electrically powered environmental sensing units indicated at 22 for sensing the forces incident to movement of the projectile through barrel 10, the antenna 18 emitting a signal proportional to the movement of the projectile as sensed by units 22 or other environmental factors. An example of this type of system is disclosed in U.S. Patent No. 2,517,133 to H. Porter.

Referring to FIGURE 2, casing 14 is internally threaded at its forward end as at 24 for threadedly receiving a locking ring 26 which joins nose portion 16 to the body portion of projectile 12. A cone-shaped liner 2S separates the projectile nose and body portions and has a radial flange 30 which is clamped between ring 26 and a shoulder 32 on casing 14, whereby liner 23- is retained behind nose portion 16. A generally cylindrical body member, preferably formed of a plastic insulating material, is received within ring 26 and secured thereto as by bolts 36 passing axially through peripheral openings formed in a diametrically enlarged portion of member 34 for endwise threaded engagement into ring 26. Pins 38 extend through radial openings formed in body member 34 with the base of the recess opening forwardly through the reduced diameter stepped down forward end portion 42 of body member 34 and the apex of recess 40 terminating coincidentally with the rear face of member 34. A Windshield assembly generally indicated 46, comprises a nose ring 47 having an internal cylindrical portion which is received about the reduced diameter end portion 42 of body member 34. The inner annular face 48 of windshield assembly 46 is formed to provide a continuation of the walls of conical recess 40 whereby the conical recess opens through the forwardmost nose portion of the projectile 10. Windshield assembly 46 also includes an external liner 49 which is suitably secured to windshield 46 about its forward end and is internally threaded about its rear end for threading engagement on ring 26 whereby nose portion 16 presents the usual streamlined external configuration.

A hemispherical recess 50 is formed through the rear face 44 of body member 34 and is laterally offset from the longitudinal axis of member 34 so that the apex of conical recess 40 lies on or intersects the periphery of the diametrical plane of hemispherical recess 50 which plane extends normal to the longitudinal axis of conical recess 40. In this manner, an aperture 52 is formed which opens through the wall of conical recess 40 adjacent the apex thereof into hemispherical recess 50. A frusto-conical base member 54, preferably formed of a plastic insulating material, is coaxially secured against the rear face 44 of body member 34 as by screws 58. A hemispherical recess 56 is formed through the larger base of member 54 and is laterally offset from the longitudinal axis of body 54 so that such axis lies on or intersects the periphery of the diametrical plane of hemispherical recess 56 which plane extends normal to the longitudinal axis of base member 54. When members 34 and 54 are circumferentially aligned as shown, hemispherical recesses 54) and 56 register one with the other to form a laterally offset spherical cavity.

A passage 60 is formed through base member 54 opening into recess 56 and through the smaller face of body 54. It will be noted that passage 69 opens into the spherical cavity on a radius angularly offset from the radius coincident with the diameter of the spherical cavity for reasons as will presently become clear. A suitable opening 62 is formed through the apex of liner 28 whereby antenna wire 18 passes coaxially through conical recess 40, through aperture 52 into the spherical cavity, and through passage 60 and opening 62 for connection to sensors 22.

When projectile 10 is fired, it is seen that antenna wire 18 is forced through opening 52 into the spherical cavity by the inertia of the wire. Wire 18 impacts substantially tangentially against the surface of the spherical cavity and tends to follow the surface as additional wire feeds through opening 52. Accordingly, it will be seen that the wire 18 impacts only against a curved surface and at a very slight angle thereto whereby the tendency of the r wire to break, as in conventional wire takeup cones wherein the wire impacts against fiat surfaces normal to the wire, is virtually eliminated. Additionally, as wire 18 impacts against the curved surface of the spherical cavity, it tends to follow the curved surface having the largest diameter, that is to say, the curved surface lying in a diametrical plane paralleling the longitudinal axis of projectile 10. Since passage 60 opens into the spherical cavity at a point offset from this plane, the collecting wire is prevented from impacting directly against the relatively rigid wire portion entering passage 69 thus precluding any tendency of the wire to break at the point of attachment of the wire to the projectile. Moreover, it is seen that the wire does not impact against previously collected wire but rather continuously impacts against the curved surface. This occurs because the collected Wire continuously moves about the spherical surface whereby the destructive impact force of the wire being collected is dissipated.

Accordingly, it is seen that the objects of the present invention have been fully accomplished in that there is provided an improved wire takeup cone which virtually eliminates breaking the wire through the impact forces of the wire against the nose portion of the projectile.

v Moreover, it is seen that the wire impacts against a curved surface at a slight angle thereto and moves about the curved surface to dissipate the impact force thereof. Additionally, by locating the aperture feeding the wire into the spherical cavity such that the wire enters substantially tangentially to the surface of the cavity, the collected wire is continuously moved out of the way of the incoming wire whereby the latter is precluded from impacting against the collected wire.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a projectile having a nose portion adapted to collect a wire extending from the projectile outwardly through the barrel of a gun as the projectile traverses the gun barrel, a body member carried by said nose portion and having a spherical cavity formed therein and means defining a passage opening into said spherical cavity through said body member in a substantially tangential direction for guiding the wire into said spherical cavity.

2. Apparatus according to claim 1 in combination with means carried by said projectile for sensing projectile environmental information, means responsive to said sensing means for recording such information, means defining a second passage through said body, and said wire being connected to said sensing means and passing through said second passage into said spherical cavity and through said first passage for connection to said recording means.

3. In a projectile having a nose portion adapted to collect a wire extending from the projectile outwardly through the barrel of a gun as the projectile traverses the gun barrel, a body member carried by said nose portion and having a spherical cavity formed therein laterally ofiset from the longitudinal axis of said projectile and means defining a passage opening into said spherical cavity through said body member for guiding the wire into said spherical cavity, said passage means extending substantially coincident with the longitudinal axis of said body member and opening tangentially into said spherical cavity.

4. In a projectile having a nose portion adapted to collect a wire extending from the projectile outwardly through the barrel of a gun as the projectile traverses the gun barrel, a body member carried by said nose portion and having a spherical cavity formed therein laterally offset from the longitudinal axis of said projectile and means defining a passage opening into said spherical cavity through said body member, said passage means including a conical recess formed in said body member extending coaxially of said projectile and opening through the forward end of the nose portion of said projectile, said conical recess opening into said spherical cavity adjacent the apex portion thereof.

References Cited UNITED STATES PATENTS 2,514,297 7/1950 Smith et a1. 73-167 2,517,133 8/1950 Porter 73l67 2,755,439 7/ 1956 Whitmore 73--167 XR FOREIGN PATENTS 721,395 6/1942 Germany. 737,589 7/ 1943 Germany.

LOUIS R. PRINCE, Primary Examiner 20 JEFFREY NOLTON, Assistant Examiner 

